Evaluating Alfalfa Stands
It is important this coming spring to evaluate your alfalfa stands for density and health. When a thin stand is detected early, there is time to improve or renovate the stand. The following methodology comes from the University of Ohio Extension and can be applied throughout all alfalfa-growing regions.
Throughout the lifetime of your alfalfa, it is normal for thinning to occur. At the same time, older alfalfa plants tend to have more stems and produce more from one plant. As you are looking at your alfalfa stands, there are two ways to determine the health and density: number of plants per square foot or number of stems per square foot. For both of the following methods, sample at least 4-6 areas throughout the field.
Plants per Square Foot
- Count the number of plants per square foot in multiple areas throughout the field. For a stand that is 3 or more years old, there should be at least six plants in every square foot area you are checking.
- You also need to make sure those plants are healthy in order to determine if they will be productive to you. Take a look at the crown and root health. Roots cut open lengthwise should be white and firm, if they are discolored or seem soft, they are not healthy. A stand is considered healthy if fewer than 30% of observed roots show discoloration.
- Observe the crowns of existing plants. They should have shoots growing evenly around the grown that look strong and healthy.
- The stand will need improved or renovated if over 50% of the examined plants show any signs of root or crow rot including discoloration or weak growth.
Stems per Square Foot
- Allow for 6 inches of growth to occur this spring.
- In multiple areas throughout the field, count the number of stems present in a square foot area.
- 54+ healthy stems = stand should stay in production
- 40-54 healthy stems = stand should stay in production, but could have reduced yield without addition of grasses or other legumes
- Less than 40 healthy stems = stand should be interseeded into to produce adequate forage or should be renovated
- To determine a healthy stem, crown, and plant, use the same guidelines as the plants per square foot method.
Stay ahead of the game with your alfalfa stand and watch for recommendations from Beyond Agronomy on what to interseed into your stands!